X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;ds=sidebyside;f=kernel%2Fevents%2Fring_buffer.c;h=cd55144270b5401030f4b5ce5576f97b6b976b63;hb=0335cd6c4f7e8d8d6f2644f5dc8a1028182055de;hp=97fddb09762b0dc815af7d1f674993d87cd45574;hpb=22b154365fbc096a46d936ec1f462ef8b9bd1f05;p=~andy%2Flinux

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 97fddb09762..cd55144270b 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -326,11 +326,16 @@ void rb_free(struct ring_buffer *rb)
 }
 
 #else
+static int data_page_nr(struct ring_buffer *rb)
+{
+	return rb->nr_pages << page_order(rb);
+}
 
 struct page *
 perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff)
 {
-	if (pgoff > (1UL << page_order(rb)))
+	/* The '>' counts in the user page. */
+	if (pgoff > data_page_nr(rb))
 		return NULL;
 
 	return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE);
@@ -350,10 +355,11 @@ static void rb_free_work(struct work_struct *work)
 	int i, nr;
 
 	rb = container_of(work, struct ring_buffer, work);
-	nr = 1 << page_order(rb);
+	nr = data_page_nr(rb);
 
 	base = rb->user_page;
-	for (i = 0; i < nr + 1; i++)
+	/* The '<=' counts in the user page. */
+	for (i = 0; i <= nr; i++)
 		perf_mmap_unmark_page(base + (i * PAGE_SIZE));
 
 	vfree(base);
@@ -387,7 +393,7 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 	rb->user_page = all_buf;
 	rb->data_pages[0] = all_buf + PAGE_SIZE;
 	rb->page_order = ilog2(nr_pages);
-	rb->nr_pages = 1;
+	rb->nr_pages = !!nr_pages;
 
 	ring_buffer_init(rb, watermark, flags);